1. Field of the Invention
The present invention relates generally to an image reading apparatus and an image forming apparatus including the same, and more particularly, to an image reading apparatus having a structure to scan both surfaces of a document and an image forming apparatus including the same.
2. Description of the Related Art
An image forming apparatus refers to an apparatus for printing an input image signal on a printing medium such as a printer, a copier, and a multifunction printer realized to combine functions of the printer and the copier. To be specific, the multifunction printer performs a function of printing image information input from an external apparatus such as a computer, a function of reading image information recorded in a document, a copy function of printing scanned and input image information, and a facsimile function of transmitting the scanned information to a remote place through a communication line.
A composite image forming apparatus includes an image reading apparatus to perform the above-described functions. A conventional image reading apparatus is disclosed in U.S. Pat. No. 5,430,536.
The disclosed image reading apparatus includes an input tray on which the document to be scanned is placed, an output tray on which the scanned document is placed, and a U-shaped document path formed between the input tray and the output tray. The image information recorded on one surface of the document that passes through a document path is scanned by a raster input scanner (RIS). Also, the disclosed conventional image reading apparatus includes a duplex document path connecting a lower side of the RIS to an upper side of the RIS on the document path in such a manner that two-sided scanning can be performed. Therefore, the document discharged to the output tray after one surface of the document has been scanned during the two-side scanning process is reversed at a specific point of time and passes through the duplex document path. The document that passes through the duplex document path passes through the document path again to completely scan one remaining surface.
However, in the conventional image reading apparatus, the duplex document path is severely inclined against the document path so that curl is generated in the document when the document passes through the duplex document path. When the curl is generated in the document, there is a high chance that the document is jammed in the image reading apparatus so that the reliability of the image reading apparatus deteriorates.
Furthermore, in the disclosed conventional image reading apparatus, when a great amount of documents is placed on the output tray, the document placed on the output tray and the document that is being scanned interfere with each other. Therefore, both surfaces of the document are not smoothly scanned or the document placed on the output tray is also dragged when the document whose both surfaces are scanned is reversed to move.